We report the unusual case of abdominal pain in a 16-year-old male who was suspected of nephrolithiasis. The pain was dependent on the position of the body and fluid intake. Initial abdominal ultrasound (US) revealed only mild dilated renal pelvis, but further US demonstrated hydronephrotic left renal pelvis. Computed tomography without contrast media excluded kidney stones; however, modelling of the left dilated renal pelvis on the vessel was suspected. Ultrasound Doppler also showed an additional artery, which crossed the ureteropelvic junction. A computed tomography angiogram clearly showed the additional left renal artery, which compressed the ureteropelvic junction. We conclude that intermittent abdominal pain that is dependent on the position of the body and fluid intake in an older child should give rise to suspicion of the presence of a crossing renal vessel. Ultrasound Doppler and computed tomography without contrast media are good methods in the investigation of intermittent abdominal pain and initial assessment of renal vessels.